The present invention relates to article holders and holding methods.
Article holders are widely used to hold articles in a suitable manner. For example, in semiconductor industry, wafer holders hold semiconductor wafers when the wafers are transported between wafer storage cassettes and wafer processing equipment. To reduce or eliminate wafer scratching and contamination, wafer holders are designed so as not to allow the wafer useful area to contact the holder. The wafer rests on holder support pins which contact the wafer only at the wafer periphery reserved for wafer handling, away from the wafer useful area.
Alternatively, a wafer is held in position by a gas vortex emitted by the holder or by a gas flow generating a reduced pressure between the holder and the wafer according to the Bernoulli principle. Such holders also do not contact the wafer useful area.
Improved holders and holding methods for wafers and other articles are desirable.